This invention relates to locking systems in general, and specifically to a locking arrangement to secure valves against intentional and unintentional adjustment.
A wide variety of types of valves are currently used in a vast array of applications. One common type of valve is known as a quarter turn valve. Quarter turn valves are used in many industrial applications, particularly in the food and beverage, pulp and paper, pharmaceutical, specialty chemical, and fine chemical industries. Quarter turn valves offer numerous advantages, including the ability to be turned on/off more quickly than linear (or multi-turn) valves such as gate valves. Quarter turn valves are often used in industrial applications because they can be turned on and left open until the required amount of fluid has passed through the valve. Conversely, quarter turn valves are maintained in a closed position until actuated to allow the fluid to pass there through.
Quarter turn valves are one type of rotary motion valve in that they have a component that rotates to allow or shut off flow through the valve. The valve member within a quarter turn valve may be a butterfly, ball, plug or other operating member to alternately permit and inhibit flow of the fluid through the valve. Quarter turn valves may be a two-way valve in which the rotary valve member blocks or permits fluid flow through a single inlet port and single outlet port. Alternatively, a multi-port quarter turn valve allows for flow into or out of multiple inlet and/or outlet ports. The ports on quarter turn valves may be flanged, threaded or welded ports for connection to appropriate pipes conveying the fluid to and from the valve.
The rotary valve member within a quarter turn valve is typically connected by a stem projecting from the valve body. Manually actuated quarter turn valves typically have an elongate handle mounted to the stem. The handle is rotated through an arc of generally 90° for adjusting the valve member to and between the open and closed positions. However, other rotary motion valves within the broad category of quarter turn valves often include rotary valves that rotate more than or less than 90°. Therefore, as used herein, the term “quarter turn valve” is defined as any valve that includes a rotary valve member movable between open and closed positions.
As previously discussed, quarter turn valves are commonly used for general purpose and industrial applications. Their popularity is due in large part to lower maintenance requirements, economical operation, ease of installation and continued savings throughout their operational life as compared to other types of valves. Nevertheless, it is generally desirable to secure any valve and, in particular, quarter turn valves in a desired orientation (open/closed). Unfortunately, tampering with industrial operations is often a great temptation to certain people, or organizations, by unauthorized manipulation of the valves to interrupt or interfere with industrial productions. Alternatively, unauthorized manipulation of quarter turn valves may not be a premeditated act intended to cause damage but may simply be the result of inadvertent misuse or innocent mistakes. Nevertheless, occupational health and safety organizations, such as OSHA and other work place and industrial oversight organizations, advocate more control over the operation of quarter turn valves. The ability to securely lock quarter turn valves in a desired position avoids many, if not all, of the above-described problems. By so doing, potentially catastrophic and/or injurious conditions can be avoided if the adjustment of quarter turn valves in industrial and other settings is limited to authorized operators only.
However, known techniques for locking or disabling quarter turn valves have proven to be deficient. Standard pad locks having a U-shaped clevis or shackle cannot be conveniently and securely installed on quarter turn valves to inhibit unauthorized operation. Moreover, such locking mechanisms offer convenient access for someone to saw or otherwise dismantle the exposed shackle portion of the lock.
Alternatively, removal of the handle or manual actuator on such valves may temporarily inhibit someone from unauthorized operation of the valve but does not prevent manipulation of the valve with a similar user-provided handle or other tool. Moreover, handle removal by the authorized user for later valve manipulation is inconvenient, inefficient and troublesome.
Therefore, a need exists for a secure, effective and easily implemented device to prevent the unauthorized, inadvertent or otherwise undesired manipulation of quarter turn valves.